SO-101 Robot Arm
The AI arm that learns by copying you.
- Cost
- ~US$122 per arm · ~US$230 for the pairUS parts list from the README, printing not included
- Difficulty
- 2/5
- Build time
- A weekend
- Skills
- 3D printing · Screwdriver · Some Python
Made by TheRobotStudio × Hugging Face · License Apache-2.0
The files are hosted by the maker. We never re-upload them.
What it is
A small desktop robot arm with 6 motors. It comes as a pair: the follower does the work, and the leader is a twin with a handle. You move the leader by hand, the follower copies you, and after enough repeats the free LeRobot software can learn the task so the arm does it by itself.
How it works
- Six servos (Feetech STS3215): base spin, shoulder lift, elbow bend, wrist bend, wrist roll and the gripper.
- One cable chains all six motors together, motor to motor, back to a small driver board.
- The brain isn't on the arm. The board plugs into your laptop over USB, and the laptop runs LeRobot.
- The leader arm uses different gear ratios, so it holds its own weight but still moves easily by hand.
- To teach it: record a task about 50 times, train for a few hours (GPU, Apple-silicon Mac or free Colab). The makers' demo puts a Lego brick in a bin.
What you need
- 6 STS3215 servos per arm (about US$14 each)
- A bus-servo driver board (about US$11), power supply and USB cable
- The printed parts (PLA is fine)
- A computer to run LeRobot
Parts we use
- ServosFeetech STS3215 serial bus servo, 7.4 V (19 kg·cm)Waveshare ★Amazon ★
- ServosFeetech STS3215 serial bus servo, 12 V (30 kg·cm)Waveshare ★Amazon ★
- ServosSO-ARM100/101 arm kit (servos + printed parts)Waveshare ★
- Controller boardsSerial bus servo adapter board (USB to ST/SC servos)Waveshare ★Amazon ★
- Sensors & cameras1080p USB camera, 130° wide angle (wrist/hand cam)Waveshare ★Amazon ★
- Power5 V 4 A DC power supply (5.5 mm barrel)Amazon ★
- Servos5264 3-pin servo cablesWaveshare ★
- Sensors & camerasIntel RealSense depth camera (D435i)Amazon ★
- Power12 V 5 A DC power supplyAmazon ★
- PowerUSB-A to USB-C cable (2-pack)Amazon ★
- Hardware/toolsM2/M3 socket screw assortmentAmazon ★
- Hardware/toolsPrecision screwdriver setAmazon ★
- Hardware/toolsQuick-grip table clamps (4-pack)Amazon ★
- 3D printingPLA filament 1.75 mm (Bambu Lab PLA Basic)Amazon ★
- 3D printingPLA filament 1.75 mm (Polymaker PolyLite PLA Pro)Amazon ★
★ = affiliate link. If you buy through it, we may earn a small commission at no extra cost to you. As an Amazon Associate we earn from qualifying purchases. Check the maker's bill of materials for exact quantities; prices change.
Is it for me?
A great first robot if you have, or can borrow, a 3D printer and you're curious about AI. The software needs a little comfort with Python and a terminal; Hugging Face's step-by-step guide covers it. No soldering on the kit path.
Official links
Summary written by us in plain words. Not affiliated with or endorsed by TheRobotStudio × Hugging Face. Prices and links last checked Nov 3, 2026. Are you the maker and want something changed? Email us.